The following investigations are to be undertaken which are extensions of certain unique features described earlier in the synthesis of fatty acids in mammalian tissues as well as of the enzyme concerned, e.g. fatty acid synthetase. I. The conditions under which short chain acids are synthesized by rat liver cytosol and their nature. Attempts will be made to isolate and characterize the factor claimed to be responsible for chain shortening of the products. II. Elucidate the physiological role of the beta-reductive pathway for the conversion of acetyl-CoA to butyryl-CoA before condensation with malonyl for further chain elongation. III. Investigate the characteristics of binding of NADPH and CoASH to bovine mammary fatty acid synthetase. BIBLIOGRAPHIC REFERENCES: Mechanisms of trans-crotonyl-CoA reductase activity of lactating bovine mammary fatty acid synthetase. K.A. Strom and S. Kumar. X International Congress of Biochemistry, Hamburg: July 25-31, 1976; p. 397. Kinetics of enoyl-Coenzyme A reductase activity in lactating bovine mammary fatty acid synthetase. K.A. Strom and S. Kumar, Federation Proc. (1977) 36, 876.